/* ==========================================
 * JGraphT : a free Java graph-theory library
 * ==========================================
 *
 * Project Info:  http://jgrapht.sourceforge.net/
 * Project Creator:  Barak Naveh (http://sourceforge.net/users/barak_naveh)
 *
 * (C) Copyright 2003-2008, by Barak Naveh and Contributors.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */
/* -------------------
 * CompleteBipartiteGraphGenerator.java
 * -------------------
 * (C) Copyright 2008-2008, by Andrew Newell and Contributors.
 *
 * Original Author:  Andrew Newell
 * Contributor(s):   -
 *
 * $Id: CompleteBipartiteGraphGenerator.java 1258 2013-04-18 20:27:18Z freecode4susant $
 *
 * Changes
 * -------
 * 24-Dec-2008 : Initial revision (AN);
 *
 */

package org.jgrapht.generate;

import org.jgrapht.Graph;
import org.jgrapht.VertexFactory;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/**
 * Generates a <a
 * href="http://mathworld.wolfram.com/CompleteBipartiteGraph.html">complete
 * bipartite graph</a> of any size. This is a graph with two partitions; two
 * vertices will contain an edge if and only if they belong to different
 * partitions.
 *
 * @author Andrew Newell
 * @since Dec 21, 2008
 * @param <V>
 * @param <E>
 */
public class CompleteBipartiteGraphGenerator<V, E> implements GraphGenerator<V, E, V> {

    private final int sizeA, sizeB;

    /**
     * Creates a new CompleteBipartiteGraphGenerator object.
     *
     * @param partitionOne This is the number of vertices in the first partition
     * @param partitionTwo This is the number of vertices in the second parition
     */
    public CompleteBipartiteGraphGenerator(final int partitionOne, final int partitionTwo) {

        if ((partitionOne < 0) || (partitionTwo < 0)) {
            throw new IllegalArgumentException("must be non-negative");
        }

        this.sizeA = partitionOne;
        this.sizeB = partitionTwo;
    }

    /**
     * Construct a complete bipartite graph
     */
    public void generateGraph(final Graph<V, E> target, final VertexFactory<V> vertexFactory,
                              final Map<String, V> resultMap) {

        if ((sizeA < 1) && (sizeB < 1)) {
            return;
        }


        // Create vertices in each of the partitions
        final Set<V> a = new HashSet<>();
        final Set<V> b = new HashSet<>();

        for (int i = 0; i < sizeA; i++) {

            final V newVertex = vertexFactory.createVertex();

            target.addVertex(newVertex);
            a.add(newVertex);
        }

        for (int i = 0; i < sizeB; i++) {

            final V newVertex = vertexFactory.createVertex();

            target.addVertex(newVertex);
            b.add(newVertex);
        }


        // Add an edge for each pair of vertices in different partitions
        for (final V v : a) {

            for (final V aB : b) {
                target.addEdge(v, aB);
            }
        }
    }
}

// End CompleteBipartiteGraphGenerator.java



